"""
package 包
module 模块
class 类
function 函数
"""

# 面向对象编程
PI = 3.1415926


# 类
class Round:
    # 构造函数
    def __init__(self, radius: int):
        self.radius = radius
        self.perimeter = 0.0
        self.area = 0.0
        self.get_area()
        self.get_perimeter()

    def check_input(self):
        pass

    def get_area(self):
        self.area = PI * self.radius * self.radius

    def get_perimeter(self):
        self.perimeter = PI * 2 * self.radius


if __name__ == '__main__':
    # 实例化类
    round1 = Round(10)
